Looper mechanism for sewing machines



July 1, 1.941. A. B. CLAYTON LOOPER MECHANISM FOR SEWING MACHINES FiledFeb. 2, 1939 s Sheets-Sheet 1 h -illL y 1, 1941. A. B. CLAYTON 2,247,570

LOOPER MECHANISM FOR SEWING MACHINES Filed Feb. 2, 1939 3 Sheets-Sheet 2July 1, 1941. A. B. CLAYTON IJOOPER MECHANISM FOR SEWING MACHINES FiledFeb. 2, 1939 3 Sheets-Sheet 3 Patented July 1, 1941 LOOPER MECHANISM FORSEWING MACHINES Andrew B. Clayton, Union, N. J., assignor to The SingerManufacturing Company,

Elizabeth,

N. J., a corporation of New Jersey Application February 2, 1939, SerialNo. 254,139

11 Claims.

This invention relates to improvements in looper-mechanisms for sewingmachines and particularly for chain-stitch sewing machines in whichendwise and sidewise movements are imparted to a looper for cooperationwith a reciprocating needle in the formation of chainstitches.

The primary object of the present invention is the provision of a sewingmachine high-speed looper-mechanism wherein the actuating connectionstherefor are disposed within a closed lubricant-chamber and adapted tooperate in a bath of oil with only the looper-shaft and driving shafttherefor projecting outwardly from the lubricant-chamber throughoil-tight connections.

A further object of the invention is to provide a looper-mechanismwherein the loopers are supported directly upon the looper-shaft so thatadditional loopers may be added for multiple line stitching by merelydrilling suitable looper-receiving apertures into the looper-shaftspaced apart according to the gauge requirements and inserting suitableloopers therein.

A still further object of the invention is to provide a looper-mechanismof the above type with means whereby the looper may be moved to aposition where it is readily accessible for threading.

The foregoing and other objects of the invention, together with meanswhereby the same may be carried into effect, will best be understoodfrom the following description of one form or embodiment thereofillustrated in the accompanying drawings. It will be understood,however, that the particular mechanism described and shown has beenchosen for illustrative purposes merely, and that the invention, asdefined by the appended claims, may be otherwise practiced withoutdeparture from its spirit and scope.

In the drawings,

Fig. l is a side elevation, partly in section, of a sewing machineembodying the present invention.

Fig. 2 is a top plan view of the sewing machine bed with the bracket-armstandard in section, and with the cloth-plate and housing cover removedso as to disclose in detail the looper-actuating mechanism.

Fig. 3 represents an enlarged vertical sectional view takensubstantially along the line 33, Fig. 2.

Fig. 4 represents an enlarged vertical view, partly in section, takensubstantially along the longitudinal axis of the looper-shaft,illustrating the looper throw-out mechanism.

Fig. 5 represents a vertical sectional view taken substantially alongthe line of scam formation, showing, in full lines, the looper in normaloperating position and, in dotted lines, the looper in threadingposition.

Fig. 6 represents an enlarged perspective view of the oscillatable andendwise movable bushing and the disengageable tooth which is securedupon the looper-shaft.

As represented, the machine is constructed with the usual bed I fromwhich rises a standard 2 supporting an overhanging bracket-arm 3terminating in a head 4. Journaled in suitable bearings in the bed I isa main-shaft 5 extending longitudinally thereof and provided upon itsforward portion with eccentrics (not shown) for actuating the feedingmechanism and in its rearward portion with a needle-actuating crank 6.

'The crank 6 is embraced by a strap 1 at the lower end of the pitman 8whose opposite end is connected to the rearward end of a pivotallymounted needle-lever 9 fulcrumed substantially midway its ends upon afulcrum-stud i0 threaded into the bracket-arm 3. The needle-lever 9 atits forward end is connected to a needle-bar H carrying at its lower endlaterally spaced needles l2.

The material is held upon the work-support or throat-plate t3 by apresser-foot I4 secured upon the lower end of the usual spring-biasedpresserbar l5 mounted in the head 4.. Cooperating with the presser-footis a feed-dog l6 ad ustably secured upon a feed-bar I1, which is raisedand lowered by a suitable eccentric 18 on the mainshaft 5, and whichfeed-bar I1 is moved back and forth through a connection with afeed-rocker l9, which feed-rocker in turn is operated by a pitman 20connected to an adjustable eccentric 2| on the main-shaft 5. It is to beunderstood that the length of stitch can be adjusted by merely settingthe eccentric 2| to the desired eccentricity.

Cooperating with the needles I 2 are two loopers 22, each of which isprovided with a blade 23 having at its forward end the usual thread-eye2iand at its rearward end a self-threading eye in the form of adetachable hook 25. In Fig. 5, it will be seen that each looper 22 isformed with a cylindrical shank 26 adapted to he received in an aperture21 in the looper-shaft 28 and secured in set position by a screw 29threaded into the looper-shaft 28. The salient advantage of mounting theloopers upon the looper-shaft in the manner just described is thatadditional loopers may be added by simply drilling more looper-receivingapertures in the looper-shaft observed that the looper-shaft 28 isjournaled at its forward end in the bearing lug 29 and at its rearwardend in an oscillatable and endwise movable bushing 30 penetrating thewall 3| oi the closed lubricant-chamber 32, and restricted to movementon a fixed axial line, which in the present case is the longitudinalaxis of the bushing 30. During the normal operation of the machine, thelooper-shaft 28 partakes of the same movements of the oscillatable andendwise movable bushing, which movements impart to the loopers theirusual loop-seizing and -shedding movements and their sidewise movements.The mechanism utilized to obtain these movements is completely housedwithin the lubricant-chamber 32 and is splash-lubricated by the oilcontained therein.

The oscillations of the bushing 30, or the loopseizing and -sheddingmovements of the looper, are derived preferably from an eccentric 33through mechanism comprising a pitman 34 connected to an upstandingrock-lever 35 secured upon one end of a stub-shaft 38 journaled in abearing lug 3'! provided adjacent the bottom of the lubricant-chamber32. Secured upon the other end of the stub-shaft 36 is an upwardlyinclined rock-lever 38, the upper end of which is connected by a link 39to a crank-arm '48 formed integral with the enlarged inner end,

or head 38', of the bushing 38. In order to provide for universalmovement between the link 39 and the crank-arm 48, the points ofconnection of the link 39 with the rock-lever 38 and the crank-arm 48are preferably of the so-called ball-and-scket type.

The endwise movement of the bushing 30 or in other words, the sidewisemovement of the looper, is derived from an eccentric 4| on themain-shaft through a pitman 42 connected to one arm 43 of a bell-cranklever 44 pivoted. upon a vertically disposed fulcrum stud 45 received inthe aperture 48 in the bed I and fixed therein by the set-screw 41, Fig.3. The other arm 48 of the bell-crank lever 44 is formed as a yoke, the

respective arms of which carry rollers 49 which enter an annular groove58 formed in the head thereby, impart to the bushing 38 and hence to theloopers 22 the requisite motions for stitchformation.

In order to render the loopers readily accessi-- ble for threading,means is provided whereby the loopers may be shifted from beneath thethroatplate l3 forwardly toward the operator and into the positionillustrated in dotted lines in Figs. 4 and 5. The means by which theshifting of the loopers is efiected is best shown in Fig. 4. From thisfigure, it will be observed that the loopershaft 28 is journaled in thebushing 30 and is connected to operate therewith through the medium of adisengageable tooth 5| adapted to be received in a radial recess orgroove 52 formed in the face of the head 30' of the bushing 38. Thetooth 5| is normally held seated in the radial recess 52 by thecoil-spring 53 which encircles the looper-shaft 28 and acts between theouter end of the bushing 30 and a collar 54 fixed on the looper-shaft28. To facilitate the timing of the loopers 22 with the reciprocatingneedles l2, the base of the tooth 5| is formed as a split collar 55which is frictionally clamped upon the inner end of the looper-shaft 28by the screw 56. In the timing of the machine, it will be understoodthat the screw 55 can be retracted and the tooth 5| turned about thelooper-shaft 28 until the correct cooperation between the loopers 22 rand the needles I2 is established.

In order to retract the loopers 22 for convenient threading, thelooper-shaft 28 is manually shifted in an endwise direction toward thestandard 2 of the machine, thereby compressing the coil-spring 53 anddisengaging the tooth 5| from the radial recess 52, as shown in dottedlines in Figs. 2' and 4. The looper-shaft 28 may then be movedcircularly relative to the movable bushing 38 so as to bring the loopers22 out from beneath the throat-plate l3. In this retracted position thesewing threads may be readily inserted into the thread-eyes 24 of theloopers 22. In repositioning the loopers for sewing after they have beenthreaded, it is necessary only to manually turn the looper-shaft 28until the tooth 5| and radial recess 52 in the bushing 38 are inalinement with oneanother, when these parts will become interlocked andheld in this position by the coil-spring 53. To assist the operator inshifting the looper-shatt from one position to another, the latter hassecured upon its outer end a knurled thumb-button 51 which is inposition beneath the work-support for convenient manipulation by theoperator.

From the above it will be apparent that I have provided a high-speedchain-stitch loopermechanism in which the actuating connections thereforare disposed within the closed lubricant-chamber 32 and are adapted tooperate in an oil mist created by the contact with the oil in the bottomof the lubricant-chamber 32 of the oil-scoop or agitator 58 formed uponthe pitman 42. The oil-laden atmosphere in the chamber 32 thoroughlylubricates all the bearing points while the machine is operating.

Access to the mechanism within the closed lubricant-chamber 32 is gainedby removing the cover-plate 59 secured in place by screws 50. A gasket6| is interposed between the cover-plate 59 and the top of the walls 3|of the lubricantchamber 32 to prevent the egress of oil. To permit thereplenishment of lubricant, the coverplate 59 is provided with aremovable plug 62, and the amount of lubricant in the chamber. isindicated ona removable oil-gauge rod 63 extending into thelubricant-chamber through the rear wall thereof.

While I have provided a sewing mechanism having a splash-lubricatedlooper-mechanism, the loopers themselves and thread are maintained dryand uncontaminated by oil. By providing a closed lubricant-chamber thelooperactuating mechanism will require attention only at protractedperiods for the purpose of oil replenishment or renewal.

Having thus setforth the nature of the invention what I claim herein is:

1. In a sewing machine, a frame, a closed lubricant-chamber supportedthereby, an actuating shaft extending through at least one wall of saidchamber, mechanism disposed within said chamber and actuated by saidshaft. a bushing extending through at least one wall of said chamber andadapted to be actuated by the mechanism within said chamber, and a shaftjournaled in said bushing and releasably connected thereto so that saidshaft may be shifted relative to said bushing.

2. In a sewing machine, a frame, a closed inbricant-chamber supportedthereby, an actuating shaft extending through at least one wall of saidchamber, mechanism disposed within said chamber and actuated by saidshaft, a bushing extending through at least one wall of said chamber andadapted to be actuated by the mechanism within said chamber, alooper-shaft journaled in said bushing, a looper carried thereby, andmeans for releasably connecting said loopershaft to said bushing so thatthe looper can be shifted into threading position.

3. In combination, a looper shaft, a looper carried thereby, a bushingin which said loopershaft is journaled, means for actuating saidbushing, and means for releasably connecting said looper-shaft to saidbushing so that the looper can be shifted to a position facilitating thethreading thereof. g

4. In combination, a looper-shaft, a looper supported thereby, a bushingcoaxial with and supporting one end of said looper-shaft, means foractuating said bushing, and yieldable means for. connecting saidlooper-shaft to said bushing to permit the looper supported by saidlooper-shaft to be shifted into threading position.

5. A sewing machine looper-mechanism having, in combination, alooper-shaft, a looper supported thereby, a bushing in which saidloopershaft is journaled having a recess formed therein, means foractuating said bushing, and a tooth of said lubricant-chamber above thehorizontal plane of the longitudinal axis of the actuating shaft foraxial movement, and mechanism housed within said chamber for connectingsaid loopershaft to said actuating shaft and imparting to said looperloop-seizing and -shedding movements, said mechanism having a portionthereof disposed so that during its movement it contacts the lubricantin said chamber and splashes the same h hout said chamber.

9. In a sewing machine, a frame including a work-support and anoverhanging head, a closed lubricant-chamber beneath said work-support,

an actuating shaft journaled in at least one wall and releasablyconnected to said bushing, and

secured upon said looper-shaft and adapted to be received in the recessformed in said bushing.

porting a portion of said looper-shaft and having a recess formedtherein, means for actuating said bushing, a tooth secured upon saidloopereshaft and adapted to be received in the recess formed in saidbushing, and a spring for maintaining said tooth seated in said recess.

7. In a sewing machine having a frame including a bed, a rotary shaftjournaled in said bed, a bushing mounted in said bed for movement on afixed axial line, a looper-shaft releasably connected to said bushingand having formed therein an aperture, a looper provided with a shankadapted to be received in said aperture, and mechanism actuated by saidrotary shaft and connected to said bushing for moving the latter on afixed axial line.

8. In a sewing machine, a frame including a work-support and anoverhanging head, a closed lubricant-chamber beneath said work-support,an actuating shaft journaled in at least one wall of said chamber abovethe level of the oil con-' tained therein, stitch-forming devicesincluding a threaded needle sustained by said overhauling head and acooperating chain-stitch looper beneath said work-support, alooper-shaft supporting said looper and iournaledin atleast onewallmechanism housed within said chamber for connecting said bushing to saidactuating shaft to impart to said looper loop-seizing and -sheddingmovements, said mechanism contacting the lubricapt in said chamber tosplash oil on the operating parts within said chamber during theoperation of the machine.

10. A sewing machine having in combination, a frame including awork-support and an overhanging head, a closed lubricant-chamber beneathsaid work-support, an actuating shaft journaled in at least one wall ofsaid chamber above the level of the oil contained therein.'

stitch-forming devices including a threaded needle sustained by saidoverhanging head and a cooperating chain-stitch looper beneath said 7work-support, a looper-shaft supporting said looper and journaled in atleast one wall of said lubricant-chamber above the horizontal plane ofing formed at one end thereof an enlarged head provided with a reces inthe face thereof, means connected to the head of said bushing foractuating the same, and a tooth secured upon said looper-shartandadapted to be yieldingly maintained in the recess formed in saidbushing.

ANDREW B. CLAYTON.

